An elevator typically comprises an elevator car and a counterweight, which are vertically movable in a hoistway. These elevator units are typically interconnected by ropes (later referred to as upper ropes) that suspend these elevator units on opposite sides of one or more rope wheels mounted higher than the elevator units. For providing force for moving the suspension ropes, and thereby also for the elevator units, one of the wheels is typically a drive wheel engaging the upper ropes. In addition to the upper ropes, the elevator may need to be interconnected by ropes which hang from the elevator car and the counterweight, and pass around rope wheels of a device (often referred to as a compensator) mounted at a stationary location which is lower than the elevator car and counterweight. This type of ropes (later referred to as lower ropes) are often used to provide compensation for the weight of the hoisting ropes. Particularly, in this way the unbalance, which is caused by the upper ropes in situations where the elevator car is run to its extreme position, can be eliminated. However, these ropes may alternatively or additionally be used to provide so called tie-down function for the elevator. The upper ropes and/or the lower ropes may be round in cross-section or belt-like.
In prior art document EP3056461B1 problems related to tension differences between successive parts of an individual rope as well as unequal rope tension between adjacent ropes have been recognized and solved. The problems have been noticed to be particularly likely when the ropes are belt-like and each of them passes along a cambered shape of a rope wheel. In the aforementioned prior art document a solution to such problems has been provided by aid of a rope assembly where the rope wheels are mounted coaxially on the frame via bearings such that they are rotatable relative to the frame as well as relative to each other, wherein the rope wheels share a central shaft which is non-rotatable relative to the frame. A hollow cylinder surrounds the central shaft, and there are bearings radially between the shaft and the cylinder, as well as radially between each of the rope wheels and the cylinder. The cylinder can rotate around the shaft, and the bearings between the cylinder and the rope wheels provide that the rope wheels need not rotate with exactly the same rotational speeds. A drawback of the presented kind of solution is that it is sensitive to obstructions of free rotation between the rope wheels. It has come up a need for an improved solution in this respect.